Lots of people use it (I use it for all my personal stuff) and it sees regular updates. [0] I think it coordinates well with modern client-side frameworks like Mithril (... and experts agree [1]). It has kept up with the new stuff in javascript, and it often does the new stuff better than JS. Example: in coffeescript you don't need the goofy function declaration flags that JS requires: "*" and "async". In coffeescript a generator is a function that yields and an async function is a function that awaits. This is clearly better.
Obviously, Typescript is more appealing to management. It may not be obvious from this thread, but bragging about how old-n-busted coffeescript is compared to... whatever was a lot cooler a couple of years ago than it is now. Nowadays the cool kids complain about npm or rollup or something.
I do Rails full time and most the CoffeeScript lives in the "legacy" side projects. Most projects I'm on have moved to vanilla JavaScript or ES6 via Webpack.
I don't think it's dead (it's still popping up), but I think it's time has passed.
Obviously, Typescript is more appealing to management. It may not be obvious from this thread, but bragging about how old-n-busted coffeescript is compared to... whatever was a lot cooler a couple of years ago than it is now. Nowadays the cool kids complain about npm or rollup or something.
[0] https://github.com/jashkenas/coffeescript/commits/master
[1] https://mithril.js.org/signatures.html#splats